It is known to provide an actuator for an inhaler (e.g. a metered dose inhaler (MDI)) for delivering drug by inhalation, which actuator comprises a housing arranged for receipt of a valved canister containing drug. The canister typically comprises a body, which includes a base and a head and defines a chamber, and a valve stem which extends from the body and from which drug is in use delivered on actuation of the canister. The actuator also comprises an outlet, which is arranged for receipt by the mouth or nose of a user and through which a user in use inhales. The actuator further comprises a nozzle assembly, which provides for delivery of drug through the outlet, wherein the nozzle assembly typically comprises a nozzle block which receives the valve stem of the canister.
In conventional actuators for use with MDI inhalers the nozzle block is provided as a single moulded part, which is usually moulded to be integral with the body of the actuator. The conventional nozzle block has an exit orifice from which aerosolized drug is expelled and thence, travels to an outlet (e.g. mouthpiece) for inhalation by a patient. Applicant finds that a more controlled passage of aerosolized drug (e.g. better channeling of drug plume) may be provided for where a nozzle outlet is provided as a separately-formed component to the nozzle block. The nozzle outlet is fluidly connected to the nozzle block and includes an outlet orifice from which drug is in use delivered. In addition, the nozzle outlet can be adapted to give a cleaner look to the outlet (i.e. mouthpiece) end of the actuator housing, which is also more amenable to cleaning by the patient.
Applicant finds that by use of such a ‘two-part assembly’ of nozzle block and nozzle outlet greater flexibility may be provided for in the overall design of the nozzle assembly. Thus, for example a more rigid (e.g. stubbier) nozzle block may be accommodated. Or alternatively, smaller jet orifice diameters (e.g. from 0.2 to 0.5 mm) may be accommodated. Additionally, different materials or combinations thereof may be use for the different parts of the nozzle assembly. The different materials may for example, be selected to have different finishes or electrostatic characteristics. Overall, the nozzle assembly is therefore much more readily tuned to provide the desired spray/travel characteristics of the aerosolized drug than is the conventional nozzle block. More ergonomic actuator forms may also be facilitated.
In addition, Applicant finds that by forming the nozzle assembly as a ‘two-part assembly’ the time of manufacture thereof may be simplified and speeded up. In more detail, the conventional single-part moulded stubby nozzle block of the well-known conventional MDI actuator requires a complex moulding tool and mould intervals of long pendency time. By contrast, the separate parts of the ‘two part’ assembly may be made simpler in form and thereby, made amenable to moulding thereof with shorter pendency times.
It is an aim of the present invention to provide an improved actuator for an inhaler for administering drug by inhalation and an inhaler including the same.